The present invention relates generally to anti-shock trousers, and more specifically to trousers that sequentially pump blood headward to aid cardiopulmonary resuscitation (CPR) and other medical procedures.
Shock is a state of massive physiological reaction to severe physical or emotional trauma, usually characterized by marked loss of blood pressure and depression of vital processes. Anti-shock trousers apply pressure to the lower body (primarily the abdomen and legs) of an injured person to increase blood return to the heart and to decrease blood perfusion in the lower body. Typical anti-shock trousers for use immediately following trauma, such as Military Anti Shock Trousers (MAST), utilize inflatable bladders to squeeze the legs and abdomen. U.S. Pat. No. 4,577,622 to Jennings teaches an improvement to conventional anti-shock trousers that includes wrapping elastic bands from the ankles to the waist to "milk" blood to the upper body.
Similar to anti-shock trousers are external cardiac assistance apparatus which sequentially fill lower body air bladders to pump blood toward the heart. An example is U.S. Pat. No. 3,866,604 to Curless et al. Also similar to anti-shock trousers are anti-G suits, a number of which include sequential application of pressure through air bladders to force blood flow to continue in the upper body. An example is U.S. Pat. No. 4,583,522 to Aronne. Another example is U.S. Pat. No. 2,495,316 to Clark et al. which, by its bladder arrangement and design, eliminates the need for complicated valving to achieve peristaltic pumping.
A recent advance in emergency treatment is the use of pneumatic CPR garments for enhancing the effectiveness of CPR. These garments synchronize the application of lower body pressure by air bladders with the application of cardiopulmonary resuscitation pressure on the chest. An example is U.S. Pat. No. 5,370,603 to Newman. Newman places a pressure sensor over the chest of an injured subject. The pressure sensor is connected to a valve for a supply of pressurized air such that when pressure is applied to the chest as part of CPR, the valve releases air from the air bladders in a lower body garment and, when pressure is released from the chest, the valve feeds pressurized air to reinflate the air bladders.
Despite these advances in the art of assisting cardiopulmonary resuscitation and the related art of anti-G suits, the prior art has failed to successfully combine the best and most appropriate features from the prior art to make a maximally successful CPR assistance garment. For example, the Newman garment applies pressure from the top down to the lower body creating the risk of blood pooling in the lower body. A particular problem with prior art CPR assistance garments is that they require substantial additional support equipment not normally found as part of paramedic equipment. That and other complexities in their use have limited their acceptance in the field by paramedics and emergency health care personnel.
Thus it is seen that there is still a need for an improved CPR assistance garment, particularly one specifically adapted for advantageous use by paramedics in the field.
It is, therefore, a principal object of the present invention to combine new features with the best and most appropriate features from the prior art to make a novel CPR assistance garment that is simple, compact, easy to use, effective in assisting CPR, and which will be readily accepted by paramedics and other health care workers.
It is a feature of the present invention that it uses a readily available conventional fire department self-contained breathing apparatus air bottle for the pressurized air supply.
It is another feature of the present invention that conventional pulmonary resuscitation face masks can be easily made part of the invention to further improve the CPR assistance effectiveness of the invention.
It is an advantage of the present invention that it produces peristaltic pumping without complicated valving mechanisms.
It is another advantage of the present invention that it is particularly suited for use away from hospitals, such as at battlefields and in the wilderness.
It is yet another advantage of the present invention that it can be used in rehabilitative medicine to provide a variety of rehabilitative therapies.
These and other objects, features and advantages of the present invention will become apparent as the description of certain representative embodiments proceeds.